Chapter 4- Kinematic Concepts of Human Movement

Question 1

What is motion? Give an example.

Answer 1

It is general motion that involves translating and rotating at the same time. The movement of a shoulder rotation with wrist and elbow joint movement.

Question 2

What is linear motion?

Answer 2

Linear motion is the movement of a body along a straight or curved path where all body parts move in the same direction at the same speed.

Question 3

What is linear distance and displacement? How are they similar, how are they different?

Answer 3

They both measure how far a body has travelled. However, distance measures the path travelled from start to finish, regardless if direction whereas displacement measures how far it is from the initial position to the final position. (think running track, o displacement but 400m in distance)

Question 4

What is speed and the equation for it?

Answer 4

the ratio of the distance covered to the time taken

distance over time

Question 5

What is velocity and the equation for it?

Answer 5

the ratio of displacement or change in position, to the taken time. It has both size and direction

displacement over time

Question 6

What is linear acceleration and the equation for it?

Answer 6

LInear acceleration refers to a change in velocity in a given period of time.

change in velocity over change in time

Question 7

Why is the ability to accelerate or decelerate important in sports?

Answer 7

For accelerating in the last 100m of a marathon, decelerating in the last into corners when mountain biking.

Question 8

What is angular motion? Give two sporting examples both inside and outside of the body

Answer 8

It is a component of general motion and involves rotation around a central axis or a fixed point. A gymnast on the high bar and the thighs rotating around the hip axis while running.

Question 9

What is torque and the equation for it?

Answer 9

Torque is what is used to describe the rotation that occurs as a result of an eccentric force being applied.

force times leverarm

Question 10

The greater the torque?

Answer 10

The greater the acceleration. Think bicycles and the size of gears or a gymnastic rotating on the high bar fully extended

Question 11

What is angular distance and displacement? How are they similar, how are they different?

Answer 11

Angular distance is the total distance covered during angular motion, whereas angular displacement is the difference between the starting point and finishing point. They are both measured in degrees. Think again high bar if they do 1.5 rotations then they would have travelled 540 degrees in distance and 180 in displacement.

Question 12

What is the equation for angular speed?

Answer 12

The total degree covered over the time taken

Question 13

What is the equation for angular velocity?

Answer 13

The change of position over the time taken

Question 14

Applying it to sports, how could you increase a ball’s linear velocity when it is thrown?

Answer 14

By increasing the angular velocity of each body segment used in the throwing motion, as it will increase the final velocity at the point of release. (think Matta and his throws with different body parts, what got the furthest)

Question 15

What is the equation for linear velocity?

Answer 15

The radius of rotation times the angular velocity

Question 16

What is angular acceleration?

Answer 16

This is how quickly a body or object changes its angular position. It can be positve, negative or zero

Question 17

What is projectile motion? Give three examples

Answer 17

It can be an object or body launched into the air and affected only by the forces of gravity and air resistance. E.g the diver’s body when diving, a cricket ball when by the cricket bat, a netball shot into the goals

Question 18

What are the two components in a projectile’s motion?

Answer 18

Vertical components which relate specifically to the height by the projectile, this is affected by gravity. Horizontal components relate to the horizontal distance covered by the projectile, these are affected by drag force

Question 19

What are each of the factors that affect the path of a projectile? Identify and explain each one, in relation to sports.

Answer 19

• Angle of release is the angle at which the object is projected into the air, affecting the horizontal distance covered. Fielder to the stumps, he higher than them, volley ball player jumping right up at 90 degrees
• Speed of release is the speed at which an object is thrown, kicked or propelled into the air, the greater the speed of release the greater the horizontal distance. If you throw a ball at 10 m/s it’s not going to go as far as one thrown at 30 m/s
• Height of release is the height at which it lands or stops. Think the 3 diagrams, shooting a basketball must be at >45, while a underarm throw to a toddler is <45 as they are below you, and a golf put would be 45